Field of the Invention
The present invention pertains generally to a marine shore power multi-adapter that utilizes three-phase electrical power service. More particularly, the invention relates to a marine shore power plug adapter system and method that enables the power system of a boat, yacht or marine vessel to connect to any variety of three-phase marine shore power electrical sources available to marine vessels at marina docking and berthing slips throughout the world.
Description of the Prior Art
Adapters for different types of electrical power supplies have been known in the prior art since the dawn of the modern power grid and improvements to the art are frequently provided. A relatively old example is provided by R. W. Rumble, entitled “Electrical Plug,” U.S. Pat. No. 3,079,475, which was awarded patent protection in 1960. According to Rumble, his invention relates to electrical fittings which can be adjusted by the user to fit any one of a multiplicity of electrical sockets, which may be made to receive plugs having either two or three pins.
Yet another relatively old example is provided by Jean-Daniel Hugly, entitled “Plug For Voltage Adaptation,” U.S. Pat. No. 3,996,546, which was awarded patent protection in 1976. According to Hugly, his invention relates to an electrical plug, more particularly a dual-voltage electrical plug which is adaptable to connect an appliance such as an electric shaver alternatively to sockets belonging to either one of two main supplies of differing voltage.
A relatively newer example is provided by Schneider et al., entitled “In-Line AC Adapter for Camping and Marine Electrical Service,” U.S. Pat. No. 6,929,515, which was awarded patent protection on Aug. 16, 2005. According to Schneider et al., their invention relates to interfacing differing electrical systems, more particularly, to an adapter for connecting electrical lines of dissimilar terminal configurations.
Yet one more example is provided by Walliser and Mazieres, entitled “Power Adapter With Interchangeable Heads,” U.S. Pat. No. 8,708,722, which was awarded patent protection on Apr. 29, 2014. According to Walliser and Mazieres, their invention relates to a power adapter with a cable port disposed on one side and a power conversion circuit to convert an input power from an alternating current (AC) power system to an output power used by a device coupled to the cable port. In addition, the power adapter allows for interchangeable heads, each with prongs suitable for different types of international AC power systems to allow the user to power electronic devices throughout the world with the use of only one power adapter.
Also known in the art are a variety of other related inventions purporting to allow electrical and electronic devices to be powered from a variety of differing types of electrical systems using adapters and/or power converters. Specific examples are too numerous to fully summarize herein.
In light of the above, there is an absence of prior art that pertain to plug adapter systems for providing high amperage three-phase electricity to a marine vessel, regardless of the type of plug configuration used on the shore power supply source. As is known in the art, many marinas throughout the world provide a shore power source at each or most of their docking and berthing slips. Each shore power source is connected to the local electrical supply grid. Typically, the shore power source at each docking and berthing slip is comprised of one or more electrical outlet or cables providing three-phase electrical power from the power grid. When docked or berthed within a slip equipped with a shore power source, the vessel's shore power cable can be connected to the electrical outlet or cable of the shore power source, providing electricity to the vessel's electrical power system.
Currently, a range of differently configured three-phase sockets are used in marinas throughout the world. IEC 60309, an international standard from the International Electrotechnical Commission for “plugs, socket-outlets and couplers for industrial purposes,” sets standards for many industrial three-phase power sockets and plugs One of the purposes of IEC 60309 is to prevent personal injury or death or damage to industrial equipment from improperly connecting industrial equipment or industrial power systems to an electrical power source to which the industrial equipment or industrial power system is not rated, specifically with regards to the voltage, frequency, and amperage of the electrical power source. To accomplish this goal, IEC 60309 provides that plugs differ in their configurations to denote compatible voltage, frequency and amperage ranges and are color coded as such. For example, the diameter of the circular plug housing will designate amperage and the location of the ground pin in relation to the clocking tab (the plastic tab on the outside of the plug housing) denotes voltage and frequency range. The ground pin can be in one of 12 locations in reference to the clocking tab with each location varying by 30 degrees or one hour if the face of the plug is thought of as a clock face with the clocking tab at the 12 o'clock location. Pins of different types of plugs can also differ in diameter and length. For example, a three-phase plug to be used with 50 Hz at 300-500 Volts has a color coded green housing with the ground pin located at the 2 o'clock location or 60 degrees with varying plug housing diameters depending on the amperage for which the plug is designed.
While some of the power sockets found at marinas internationally may follow the IEC 60309 standard, many countries may have their own standard. Generally speaking, though, most three-phase sockets found at marinas internationally will most likely be a four (4) or five (5) pin terminal variety, which have configurations that are similar to IEC 60309 sockets due to having a ground terminal typically larger in diameter than the other terminals, with the neutral terminal (in the case of a five (5) pin socket) being immediately counterclockwise to the ground terminal followed by the L3, L2, and L1 phase terminals. Four (4) pin terminal sockets will not have a neutral terminal, but the order of the phase wire terminals will be the same.
While in practice it would be ideal for sockets at a marina to follow the IEC 60309 standard or another standard based upon the voltage, frequency and amperage of the shore power source, many times the type of socket installed is based upon what was available to the installer at the time of installation. Therefore, one could easily find a 50 V, 300-500 Hz green color coded socket with a ground terminal at 60 degrees having a socket housing with a radius designating 32 amps installed on a shore power source that provides 240 V at 60 Hz with 100 amps. Therefore, prior to connecting the vessel's shore power cable to a shore power source, vessel engineers routinely check the voltage, amperage, and frequency of the shore power source to ensure compatibility with the vessel's electrical power system. While the inventor intends the invention to work primarily with vessels having power converters which have the ability to convert the voltage, frequency, and amperage of any available shore power source to the voltage, frequency, and amperage required by the vessel's electrical power system or systems, the invention could also be used for vessels without power converters as long as proper electrical standards and safety procedures are followed.
Though one may find one shore power socket configuration regularly used throughout a country or region, it is not uncommon for other socket configurations to also be used within that region. For example, there are known shore power source socket configurations that are used in each of the following regions: United States, Europe, Middle East, North Africa, the Caribbean, and South East Asia. One could easily find one of these regional configurations or others being used in a different region.
Typically, a yacht or marine vessel has a shore power cable with a plug having a configuration compatible to the socket configuration of the region where the vessel is manufactured or where the vessel is to be berthed or is currently berthed. When the vessel moves to a marina that uses a different socket configuration from the plug currently installed on the vessel, the typical operating procedure for connecting the vessel to a shore power source at a new marina is: (1) sourcing the correct plug to match the socket provided at that particular location; (2) testing the shore power source socket to determine the correct phase and wire locations; (3) cutting and stripping the vessel's shore power cable and enclosed wires; and (4) installing the sourced plug on the vessel's shore power cable by hard wiring the sourced plug to the vessel's shore power cable wires. There are a number of problems with this procedure. First, sourcing the correct power plug for the location is sometimes very difficult and may take up to a week or longer, requiring the vessel to rely upon its generators for power. Generators are typically loud and therefore frowned upon being used in marinas because no one, including the vessel's owner or its marina neighbors, wants to hear the annoying hum of generators. Second, installing the newly sourced plug can be dangerous if it is wired incorrectly. Third, having to strip the Vessel's expensive power cable every time a new plug is installed shortens the power cable meaning it will eventually need to be replaced when it gets too short. Finally, having to disassemble the vessel's power cable plug every time it docks in a marina having a shore power socket with a different plug configuration creates wear and tear on the power plugs and on the vessel's power cable eventually resulting in one or both needing to be replaced.
In addition, it is not uncommon for marinas to have shore power sources which require the vessel to be hardwired to either a power terminal on the dock or hardwired to the end of a shore power cable which instead of having a socket installed has only bare wires. In these instances, the standard operating procedure is to hard wire the vessel's shore power cable to the marine shore power source following a similar procedure as outlined above.
An alternative operating procedure would involve having multiple cable sets, each of which converts the type of plug configuration installed on the vessel to only one other configuration, thus requiring multiple sets of cables. Each cable set is very expensive and bulky, taking up prime storage space within the vessel. Even if a vessel is equipped with multiple sets of cables, sometimes a vessel will arrive at a marina that has a power plug configuration that is wholly different from any known configuration for which the vessel is equipped, thus requiring the installation of a new power plug following the procedure discussed above.
The present inventor herein has attempted to develop a third option that allows a vessel to be quickly and efficiently connected to a shore power source regardless of whether the configuration of the socket installed on the shore power source, if any, known or unknown.